Drill bit



N0v.12,1935. l F, THAHELD 2,020,625

DRILL BIT Filed July ll, i935 4l Sheets-Sheet l Nov. 12, 1935.

21mm l Fm A. Mae/d' @www Nov. 12, 1935. F. A. THAHELD DRILL BIT Filed July ll, 1935 4 Sheets-Sheet 5 F. A. THAHELD Nov. 12, 1935.

DRILL'VBIT v Filed July l1, 1955 4 Sheets-Sheet 4 @Hoe/MMA d'7 /sr/Q Patented Nov. n 12, 1935 UNITED sTATss rArELNr oFElcE mnu. Brr

Ferl A. mma, palm, Gulberson Corporation,

tion oi' Delaware Tex., assigner to The Dallas, Tex., a corpora- This invention relates to new and useful iniprovements in drill bits.

One object of .the invention'is to provide an improved: drill bit having the usual conical cut ters mounted thereon, which is adapted for use in the drilling of wells, and particularly in drilling in hard formations.

An important object oi' the invention is to provide an' improved roller bit having cutter axles, and conical cutters mounted eccentrically on said shafts so that in operation the cutters undergo4 an oscillating or wobbling motion. whereby a choppingaction is imparted to the cutters which make for increased etliciency in drilling.

Another object of the inventionlis to provide improved means for 'mounting a conical cutter on the cutter axle of a roller bit, in such a way that the longitudinal axis' of the cutter is at an inclination with relation to the longitudinal axis of the axle, whereby the cutter will oscillate in its rotation, said mounting being arranged to bear the increased thrust occasioned by the oscillation oi." the cutter.

A further object oi Ithe invention is to provide means for eccentrically mounting conical cutters on a drill bit, said mounting being simple in construction, whereby assembling is simpliiied and cost reduced to a minimum.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure 1 is a view, partly in elevation and partly in section oi' a roller bit constructed in accordance with the invention,

Figure'2 is a-vertical sectional view, taken on the line 2-2 of Figure 1,

Figure 3 is a vertical, sectional view of one oi the conical cutters,

Figure 4 is partial bottom view of one of said cutters,

Figure 5 is a view, partly in elevation and partly in section of another form of the invention,

Figure 6 is an end elevation of the same,

Figure 7 is a view, partly in vsection and partly in elevation ot another form of the invention, and,

Figure 8 is a transverse sectional view taken on the line 8--8 of Figure 7.

In the drawings, the numeral II t, 1

bit body or head having a reduced, tapered vpin I I,

Vor other drill stem connection at its upper end.

The pin is surrounded by an outwardly directed shoulder I2. The body is provided with depending legs, or hangers I3 which have their inner Il sides I3 inclining inwardly and upwardly toward the center oi' the body (Figure l). Each hanger is provided with an inwardly extending inclined cutter axle or shaft I4, the axles being located at substantially a right angle to the inner surl@ face I 3' of the hanger. It is pointed out that the axles are in the same horizontal plane.

.The lower edge of each axle is beveled at I5 and this bevel is provided with an annular recess I6. The recess is semicircular in cross section. 15 A cutter Il is mounted on each. axle and, as clearly shown in Figure 1, each cutter is conical being provided with cutting teeth I8 on its exterior surface. The teeth are shown as larger at the base of the cone and gradually smaller 2li toward the apex, although itis pointed out that the structure of the teeth is immaterial to the invention.

Since the mounting of the cutters is exactly the same, it is believed a description of one will 25 suflice.

Each cutter is provided with an enlarged cylindrical axle bore I9 which is arranged to llt over the axle or shaft I4. The bore is disposed at an inclination with relation to the longitudi- 30 nal axis ofthe cutter and is of a greater diameter than the axle. Thus, when the cutter is placed over the axle so that said axle extends axially within the bore an annular space 20 is provided around said axle. The bore has a depth sub- 35 stantially equal to the length of the axle and the bottom of the bore is provided with an annular recess 2l, semi-circular in cross section. When the axle I4 extends axially within the bore, this annular recess 2| registers with the 40 annular recess I6 in the lower edge of the axle, whereby a raceway is formed to receive ball bearings 22. 'I'hese balls being at the bottom of the axle take the longitudinal thrust upon the cutter.

Since 'the opening I9 is oiset from the longitudinal axis of the cutter, it is obvious that when the cutter has been positioned on the axle, as

` explained, the longitudinal axis of the cutter is inclined with relation to the longitudinal axis of the axle, whereby the latter is eccentrically mounted on said axle. It is pointed out that the upper face or base I1' of the conical cutter is parallel with the inclined face I3 of the hanger when said cutter is in position on said axle.

For rotatably securing each cutter on its axle, the periphery of said axle is provided with annular ridges or corrugations 23 which extend substantially the length of said axle. The inner wall of the bore I9 is formed with complementary, annular corrugations 2l so that elongated corrugated rollers 25 may be inserted in the annular space 20 around the axle. 'Ihese rollers are entered into the space 20 through an inclinedcylindrical opening 26 in the hanger or leg I3 of the bit. A portion of the corrugations 23 and 2l are cut away at 21 (Figure 2) to receive the rollers 25 and thus it is obvious that sulcient rollers may be entered to completely ll the space 20. After the rollers are in position, an elongated pin 28 is placed in the opening 26 and is of sufficient length so that its lower end terminates in alinement with the inner side I3' of the hanger member I3. This pin serves to prevent the roller in the cut-out portion 21'from being displaced upwardly. The pin may be welded in the opening, or it may be screw-threaded, or otherwise suitably secured therein. The corrugations on the rollers engaging the corrugations of the axle and bore serve to hold the cutters on the axles.

In this particular type of drill bit, the coneshaped cutters rotate to perform the cutting operation uponthe slippery bottom of the well only by the traction of their teeth and therefore, it is essential that bearing friction be reduced to a minimum. It is obvious that with the elongated, corrugated rollers, bearing friction is greatly reduced and also due to the length of the rollers, the bearing area is greatly increased, whereby the life of the drill bit is increased due to the fact that the rollers will out Wear a ball bearing, which is usually employed in the ordinary cone cutter drill.

Since the longitudinal axis of each cutter is not in alinement with the longitudinal axis of its axle, it will be seen that as said cutter rotates, it will oscillate or wobble with relation to the bottom of the hole, whereby instead of the usualv grinding action which is obtained with the cone cutters now in use, a chipping action is produced. That is, due to the eccentric mounting the rotation of the cutter will cause the teeth thereof to chop, rather than grind, the bottom of the hole. This chopping makes for more eillcient and faster drilling. It also makes for increased efilciency when drilling in particularly hard formations.

It is obvious that due to this chopping action, there will occur an increased upward thrust against the rollers 25. The corrugations 23 are so formed that one of the surfaces 23 of each corrugation are substantially at right angles to the direction of the thrust, as indicated by arrows, in Figure 1. Therefore, these surfaces 23' co-acting with the registering corrugations of the rollers 25 and shaft I4, take the thrust. Further, since a plurality of corrugations are provided, it is obvious that an increased bearing area is provided. l

In Figures 5 and 6, I have shown another form of the invention. In this form hangers 3B similar to the hangers I3 are made separate from thev as clearly shown by heavy lines in Figures 5 and 6.

In both forms, the longitudinal axis of the conbutalso bear the thrust of the cutting action. 5

Further, the size of said rollers make for increased ybearing surface and prolong the life of the bit.

It is pointed out that a plurality of ball bearings are provided to absorb the longitudinal thrust of the cutter and this increased number of ball 10 bearings aids in reducing the bearing friction to a minimum, whereby rotation of the cutters is madeeasier.

v In both the above forms, corrugated rollers have been shown as holding the cutters in posi- 15 tion but it is pointed out that the invention is not to be limited to such rollers. It would be possible to mount the conical cutters in other ways, and so long as such cutters are mounted to oscillate, the purpose of the invention is accom-A 20 plished. This mounting is shown in Figures 'I and 8, wherein the bore I9 of each cutter has a smooth surface and is provided with an annular recess I9' in its side wall. Each axle I4 is made separate from the hanger I3 and is provided with an 25 annular iiange I4'. The underside of each hanger is formed with a cylindrical recess 35 and when the upper end of the axle is inserted therein, the flange- I4 lies contiguous to the underside of the hanger. 30

For holding each cutter on its axle, a headed pin 36 is provided.' This pin has its head 31 set' within the bottom of the bore and has its shank extending upwardly through an axial opening 33 in the axle and through an opening 39 in the 3s hanger. The upper end of the pin is welded to the hanger. The lower end of the axle is reduced at I0 and when the cutter is in position on said axle this reduced portion registers with the annular recess I3' whereby elongated rollers 4|' o may be inserted between the cutter and axle. These rollers are inserted before the axle is entered into the bore I3.

The body is preferably made in two halves A and B and in assembling the device, the cutters 45 and axles are rst mounted in the hangers. The two `halves are then placed around a. sleeve 4l which has an upwardly turned lip lI on its lower end. 'Ihis lip engages an internal depending ange l2 formed at the lower end of the bore of 50 the body (Figure '1). The upper end of the sleeve is threaded to receive a collar 43 which when screwed onto the sleeve, as shown, has its lower end engaging a ange M formed at the upper end of the bore of the body. Thus, it will be 55 seen that the sleeve and collar will securely hold the halves A and B together. This structure lmakes for easy assembling and dis-assembling.

It is obvious that the rollers will carry the thrust of the oscillating cone while the headed pin serves to hold the cone on the axle. The mounting of the conical cutter of! center is the important feature of the invention and it is pointed out that the invention is not to be limited to any particular type of mounting. Although elongated rollers have been found to be satisfactory, it would be possible to substitute the usual ball bearings therefor.

What I claim and desire to secure by Letters 70 Patent is:

l. A drill bit including, a body, cutter axles on the body, and a rotatable cutter mounted on each axle and having its longitudinal axis disposed at an inclination with relation to the longitudinal axis of axle, 4whereby the cutters will oscillate in rotation.

2. A drill bit including, a body, conical cutters each having an axle bore which is disposed so that the longitudinal axis of said bore is at an inclination with relation to the longitudinal axis of the cutter axles carried by the body and arranged to engage inthe bores of the cutter, whereby rotation of the cutters on the axles will cause said cutters to oscillate, and means for securing said cutters on said axles.

3. A drill bit including, a body, a pairoi axles on the lower end of the body and disposed at an inclination in a horizontal plane, and a conical cutter mounted on each axle and having its longitudinal axis disposed at an inclination with relation to the longitudinal axis of the axle,

whereby the cutters oscillate when rotated.

4. A drill bit including, a body, a pair of axles on the lower end of the body and disposed at an inclination in a horizontal plane, a conical cutter arranged to be mounted on each axle and having an axle bore which has its longitudinal axis disposed at an -inclination with relation to the longitudinal axis of the cutter, said bore being adapted to engage over the axle, whereby rotation of the cutters on the axles will cause said cutters to oscillate, and means for securing the cutters to the axles.

5. A drill bit including, a body, a pair of hangers formed at the lower end of the body at each side thereof, axles extendiifg inwardly and inclined downwardly from the inner side of each hanger, and a rotatable cutter mounted on each axle and having its longitudinal axis disposed at an inclination with relation to the longitudinal axis of its axle, whereby the cutters will oscillate in rotation.

6. A drill bit including, a body, conical cutters each having an axle bore which is disposed so that the longitudinal axis of said bore is at an inclination with relation to the longitudinal axis of the cutter, axles carried by the body and arranged to engage in the bores of the cutter, whereby rotation of the cutters on the axles will cause said cutters to oscillate, and elongated corrugated rollers located in the bore of each cutter and surrounding the axle to fasten each cutter on its axle.

7. A drill bit including, a body, conical cutters each having an axle bore which is disposed so that the longitudinal axis of said bore is at an inclination with relation to the longitudinal axis of the cutter, axles carried by the body and arl ranged to engage in the bores of the cutter, whereby rotation of the cutters on the axles will cause said cutters to oscillate, each axle and bore being formed with annular corrugations, and corrugated rollers registering with said corrugations and located within the bore around the axle for securely fastening each cutter to its axle.

8. A drill bit including, a body, conical cutters each having an axle bore which is disposed so that the longitudinal axis of said bore is at an inclination with relation to the longitudinal axis of the cutter, axles carried by the body and arranged to engage in the bores of the cutter, whereby rotation of the cutters on the axles will cause said cutters to oscillate, elongated corrugated rollers located in the bore of each cutter and surrounding the axle to fasten each cutter on its axle, and means in thevbody for introducing said rollers into the bore of each cutter after said cutter has been placed on the axle.

9. .A drill bit including, a body, a pair of hangers formed integral with the lower end of the body at each side thereof, an axle carried by each hanger, a conical cutter arranged to be mounted on each axle and having an axle bore 5 which is disposed so that its longitudinal axis is at an inclination with relation to the longitudinal axis of the cutter, the bore of said cutter being arranged to receive one of the axles, whereby the cutter will oscillate in rotation, and means for fastening each cutter on its axle.

10. A drill bit including, a body, a pair of hangers formed integral with the lower end of the body at each side thereof, an axle carried by each hanger, a conical cutter arranged to be l5 mounted on each axle and having an axle bore which is disposed so that its longitudinal axis of the cutter, the bore of said cutter being arranged to receive one of the axles, whereby the cutter will oscillate` in rotation, and elongated 20 corrugated rollers mounted in the bore of each cutter and surrounding the axle to fasten each cutter on its axle.

1l. A drill bit including, a body, a pair of hangers formed integral with the l-ower end of the 25 body at each side thereof, an axle carried by each hanger, a conical cutter arranged to be mounted on each axle and vhaving an axle bore vwhich is disposed so that its longitudinal axis is at an inclination with relation to the longl- 30 tudinal axis of the cutter, the bore of said cutter being arranged to receive one of the axles, whereby the cutter will oscillate in rotation, each' axle and bore being formed with annular corrugations, and corrugated rollers registering with 35 said corrugations and located within the borearound the axle for securely fastening each cutter to its axle.

l2. A drill bit including, a body, a pair of hangers separate from vthe body, and arranged 40 to be secured to the lower end of the body at each side thereof, an axle carried by each hanger, a conical cutter arranged to be mounted on each axle and having an axle bore which is dis A posed so that its longitudinal axis is at an in' 45 clination with relation to the longitudinal axis of the cutter, the bore of said cutter being arranged to receive one of the axles, whereby the cutter will oscillate in rotation, and means for fastening each cutter on its axle.

13. A drill bit including, a body, conical cut' ters each having an axle bore which is disposed .so that the longitudinal axis of said bore is at an inclination with relation to the longitudinal axis of the cutter axles carried by the body and ar- 55 ranged to engage in the bores of the cutter, whereby rotation of the cutters on the axles will cause said cutters to oscillate, and elongated rollers mounted in the bore of each cutter and surrounding the axle to fasten each cutter to its 60 axle.

14. A drill bit. including. a body, hangers formed at the lower end of the body at each side thereof, axles separate from the hangers and arranged to be secured thereto, a conical cutter mounted on each axle and having its longitudinal axis disposed at an inclination with relation tothe longitudinal axis of the axle, and elongated rollers disposed between each cutter and its axle.

15. As a sub-combination in a drill bit, a cutter having an axle bore the axis of which is disposed at an inclination with relation to the lon-j gitudinal axis o1' the cutter.

16. As a sub-combination in a drill bit, a con- 75 ical cutter having an axle bore which has its longitudinal axis disposed at an inclination with relation to the longitudinal axis of the cutter.

17. As a sub-combination in a drill bit, a con- 5 ical cutter having cutting teeth formed on its exterior face, and having an axle bore in its base, the longitudinal axis of said bore being disposed at an inclination with relation to the longitudinal axis of the cutter.

FERI A. THAHELD. 5 

